I actually didn't go for my first 99 intentionally; all my friends trained Woodcutting, so I did as well, and I just managed to get 99 in the process. As for my second, I decided that Fishing was very close to Woodcutting, so I switched to that, and it was relatively easy to get to 99. Now for the ones after those two, yea those were harder to get since they were trained differently (well, before all these do-x came out)